One of the most extraordinary properties of living cells is their ability to precisely reproduce themselves through processes that transfer genetic information from one cell to the next.
However, there are times when one of the steps of information transfer, transcription, goes awry at the cellular level, potentially producing diseases such as cancer and other health disorders. Unraveling how those processes work and how substandard transcription can be prevented is a major goal of biomedical science. Progress in this area may also lead the way toward development of drugs that target the genetic transcription process in disease-causing microbes.
A research team led by Arkady Mustaev, PhD, of the Public Health Research Institute (PHRI) at the University of Medicine and Dentistry of New Jersey-New Jersey Medical School, has published a study posted online by the Journal of Biological Chemistry, that describes an effort by the investigators to understand the underlying mechanisms of high precision (fidelity) of RNA synthesis by RNA polymerase, the major enzyme that promotes the transcription process. They attempted to influence the role of active center tuning (ACT) -- a mechanism they first identified -- in the process of transcription fidelity, which is the accurate copying of genetic information.
ACT is a rearrangement of the RNA polymerase catalytic center from an inactive to a catalytically proficient state. The investigators found that both reactions of NTP polymerization and hydrolytic RNA proofreading are performed by the same active center that includes two magnesium (Mg) ions coordinated by aspartate triad. The active center is normally “turned off” since it is missing one of Mg ions. Correct NTP substrates as well as misincorporated RNA residues can promote ACT by inclusion of the missing Mg ion through establishing recognition contacts in the active center. Incorrect substrates cannot trigger ACT and are rejected. The investigators also demonstrate that transcript cleavage factors Gre build on ACT mechanism by providing the residues for stabilization of catalytic Mg ion and for activation of the attacking water causing 3000-4000-fold reaction enhancement thereby strongly reinforcing proofreading.
The suggested ACT mechanism is fundamentally different from that proposed for DNA replication enzyme, DNA polymerase (DNAP) in which the active centers for DNA synthesis and proofreading are separated and discrimination between deoxy- and ribo-substrate is achieved through strict fitting requirements for the sugar rather than through active center rearrangement. In DNAP active center carboxylates stem from rigid scaffolds, while in multisubunit RNAP they reside in an apparently flexible loop. ACT is accompanied by significant re-shaping of the loop, which would not be possible in DNAP.
This study was supported by NIH grant RO1 GM-30717-21.
Journalists who wish to speak with Dr. Arkady Mustaev should contact Rob Forman, UMDNJ Chief of News Services, at 973-972-7276 or email@example.com .About PHRI:
Rob Forman | Newswise
New Computer Model Could Explain how Simple Molecules Took First Step Toward Life
29.07.2015 | Brookhaven National Laboratory
Switch for building barrier in roots
29.07.2015 | The University of Tokyo
Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.
Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight
A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...
Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.
By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...
Argonne scientists used Mira to identify and improve a new mechanism for eliminating friction, which fed into the development of a hybrid material that exhibited superlubricity at the macroscale for the first time. Argonne Leadership Computing Facility (ALCF) researchers helped enable the groundbreaking simulations by overcoming a performance bottleneck that doubled the speed of the team's code.
While reviewing the simulation results of a promising new lubricant material, Argonne researcher Sanket Deshmukh stumbled upon a phenomenon that had never been...
A NASA camera on the Deep Space Climate Observatory (DSCOVR) satellite has returned its first view of the entire sunlit side of Earth from one million miles away.
The color images of Earth from NASA's Earth Polychromatic Imaging Camera (EPIC) are generated by combining three separate images to create a...
23.07.2015 | Event News
10.07.2015 | Event News
25.06.2015 | Event News
29.07.2015 | Physics and Astronomy
29.07.2015 | Life Sciences
29.07.2015 | Awards Funding